Conventional practice on a multi-spool gas turbine engine is to have the engine oil pump driven via the high-pressure spool of the engine. During start-up, the high-pressure spool usually turns before the low-pressure spool which drives the load so this ensures that sufficient oil pressure is available to bearings associated with the rotation of the low-pressure spool as soon as possible during the operation of the gas turbine engine to achieve good bearing life and reliability. However, in some situations or for engine types where the low-pressure spool of the multi-spool gas turbine engine would be driven before or without necessarily having to drive the high-pressure spool, arrangements where the engine oil pump is driven via the high-pressure spool may not be optimal.